Tides Marine SeriesOne shaft seals have been designed to be installed on smaller yachts, work boats and ski boats. Manufactured for shaft diameters of ¾” to 1.25” / 22mm to 30mm, there are two stern tube hose attachment options depending on if the installation has hard or soft engine mounts. For installations with rigid mounts, high engine rpm and short shaft lengths the single convolution hose is recommended, which for smaller diesel engines and softer engine mounts the multi-convoluted hose is required.